Broadly Reactive Antibodies Against Chimeric Virus-Host Antigens

描述（由申请人提供）： HIV-1从细胞膜上出芽，并将宿主蛋白质整合到其包膜中。在这项提案中，我们解决了这些宿主蛋白对HIV免疫的影响。我们将检验这样的假设，即在HIV感染期间，针对部分由宿主蛋白质和部分由病毒Env糖蛋白形成的表位产生抗体，并且这种抗体具有广泛的抗病毒活性。因此，我们提出了一个非常新颖的概念，嵌合抗原，由宿主和病毒成分之间的稳定或短暂的界面，是病毒免疫的一个特点。如果我们的假设是正确的，免疫原可以通过将病毒蛋白与保守的宿主蛋白结合来制备，从而允许高比例的保守决定簇。此外，由于嵌合抗原可能是构象的，因此可以构建基于来源于宿主/病毒界面的保守结构的独特免疫原。我们将完成以下具体目标：1）筛选与嵌合抗原结合的mAb。我们将筛选抗病毒样颗粒（VLP）或Env表达细胞的mAb（来自HIV感染的受试者），这些细胞有或没有已知在病毒体表面发生的宿主蛋白。宿主蛋白质的表达将通过RNA干扰（RNAi）来调节。将进一步评估仅与VLP或表达Env和感兴趣的宿主蛋白的细胞结合的mAb; 2）确定针对嵌合抗原的mAb的抗病毒功能。将检测抗体对一组HIV-1毒株的中和和抗体依赖性细胞介导的病毒抑制。由于我们将筛选多达1，000种单克隆抗体，并考虑至少20种宿主蛋白质作为Env形成表位的伴侣，因此如果存在嵌合抗原，我们将有很好的机会找到它们。此外，我们的筛查范围将为阴性结果提供信心。因此，我们的方法旨在充分探索在HIV感染期间发生针对嵌合抗原的抗体的假设，并且我们将获得它们存在或不存在的有力证据。如果成功的话，我们的研究将导致一个范式的转变，从抗病毒抗体反应总是针对独特的病毒表位的概念，并朝着决定性的新概念的表位从病毒加宿主。此外，我们的嵌合抗原的新概念可能会产生新的，广泛的抗病毒单克隆抗体和新的免疫原，引起广泛的抗病毒反应。发现嵌合抗原可能会对艾滋病毒预防产生深远的影响，因为它克服了有效疫苗似乎难以克服的障碍。发展HIV疫苗的一个主要障碍是缺乏能广泛激发抗病毒抗体应答的免疫原。我们提出了一种非常新颖的方法来发现这样的免疫原。如果成功，这项研究可能直接导致预防艾滋病毒感染的疫苗。

DESCRIPTION (provided by applicant): HIV-1 buds off cell membranes and incorporates host proteins in its envelope. In this proposal, we address the impact these host proteins have on HIV immunity. We will test the hypothesis that during HIV infection, antibodies are made against epitopes formed partly by host proteins and partly by viral Env glycoproteins and that such antibodies have broad anti-viral activity. Thus, we propose the very novel concept that chimeric antigens, consisting of a stable or transient interface between host and viral components, are a feature of viral immunity. If our hypothesis is correct, immunogens could be made by combining viral proteins with conserved host proteins, thereby allowing a high proportion of conserved determinants. In addition, since chimeric antigens are likely to be conformational, unique immunogens based on conserved structures derived from host/virus interfaces could be constructed. We will accomplish the following specific aims: 1) Screen mAbs for binding to chimeric antigens. We will screen mAbs (from HIV-infected subjects) against virus-like particles (VLPs) or Env-expressing cells with or without host proteins known to occur on virion surfaces. Expression of host proteins will be regulated by RNA interference (RNAi). mAbs binding only to VLPs or cells expressing both Env and a host protein of interest will be evaluated further; 2) Determine the antiviral function of mAbs directed against chimeric antigens. Antibodies will be tested for neutralization and antibody-dependent cell-mediated virus inhibition against a panel of HIV-1 strains. Since we will screen as many as 1,000 mAbs and consider at least 20 host proteins as partners with Env in forming epitopes, we will have an excellent chance of finding chimeric antigens should they exist. Moreover, the extent of our screening will provide confidence in a negative result. Thus, our methods are designed to fully explore the hypothesis that antibodies against chimeric antigens occur during HIV infection, and we will gain strong evidence of their presence or absence. If successful, our research will result in a paradigm shift away from the concept that anti- viral antibody responses are always directed against uniquely viral epitopes and toward the decidedly new concept of epitopes made from virus plus host. Moreover, our novel concept of chimeric antigens may yield new, broadly anti-viral mAbs and novel immunogens that elicit broadly anti-viral responses. Discovering chimeric antigens could have a profound impact on HIV prevention by overcoming seemingly intractable obstacles to an effective vaccine. A major obstacle to the development of an HIV vaccine is the lack of an immunogen that elicits broadly anti- viral antibody responses. We propose an exceptionally novel approach to discover such immunogens. If successful, this research may lead directly to a vaccine that prevents HIV infection.